Method for recovering nickel-cobalt-manganese black powder in short process

Abstract

The invention belongs to the technical field of resource recovery, and provides a short-process nickel-cobalt-manganese black powder recovery method which comprises the following steps: removing tungsten from an impure nickel-cobalt-manganese solution obtained by acid leaching by using a tungsten removal agent, and then adjusting the pH value through nickel-cobalt precipitate and alkali in sequence to perform precipitation and impurity removal; after impurity removal, only the manganese element is subjected to extraction and reverse extraction, and nickel-cobalt raffinate and manganese reverse extraction liquid are obtained; the nickel-cobalt raffinate is subjected to evaporative crystallization, nickel-cobalt salt crystals are obtained, a certain amount of evaporation mother liquor is reserved, one part of the evaporation mother liquor is directly returned for impurity removal, the other part of the evaporation mother liquor is subjected to precipitation, nickel-cobalt precipitates are obtained, and then the nickel-cobalt precipitates are reused for impurity removal. According to the method, the technological process is simple, impurities can be effectively removed, only manganese extraction is selected, the acid and alkali consumption and the wastewater generation amount of the extraction section are reduced, the evaporation mother liquor is reserved by controlling the evaporation crystallization degree, the evaporation mother liquor is divided into two parts to be reused in the impurity removal procedure, enrichment and recovery of nickel and cobalt can be achieved, and the consumption of alkali reagents can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of resource recovery and relates to a method for recovering nickel, cobalt and manganese black powder in a short process. Background Art

[0002] The new energy industry is a promising and promising sector. As the penetration rate of new energy electric vehicles continues to rise, lithium battery shipments are also increasing dramatically. However, this has led to a growing number of retired lithium batteries. Retired ternary lithium batteries contain important strategic metals such as nickel and cobalt, making them essential for recycling.

[0003] The current mainstream recycling process for retired ternary lithium batteries is the wet recycling process. The main process flow of wet recycling is to disassemble the retired lithium batteries after discharge to obtain black powder. The black powder can be directly leached by adding acid and reducing agent, or it can be pre-processed with lithium ion extraction and then leached. The leachate obtained by leaching is added with chemical reagents for impurity removal to obtain a preliminary purified nickel-cobalt-manganese solution. After extraction and back extraction of nickel, cobalt, manganese and other elements, a refined nickel-cobalt-manganese salt solution is obtained.

[0004] Considering that in order to improve the performance of ternary positive electrode materials, existing technologies usually dope and modify ternary materials. These doping elements include tungsten, strontium, zirconium, titanium and boron. Since the mainstream wet recovery process is to fully extract and fully reverse the three main metals of nickel, cobalt and manganese during extraction to obtain the corresponding nickel, cobalt and manganese refined solution, and the doping elements tungsten, strontium, zirconium, titanium and boron remain as impurities in the extract, these doping elements are not considered for separate removal. However, the process of full extraction and full reverse has the disadvantages of high alkali and acid consumption, large amount of wastewater generated, and high investment in extraction equipment, resulting in a corresponding increase in the cost of recovery. If the process of full extraction and full reverse is not carried out, it is necessary to consider how to efficiently separate the main metal elements and doping elements to avoid the influence of impurity elements.

[0005] It can be seen that in response to the above problems, it is necessary to carry out research on a new wet recovery process for nickel, cobalt and manganese black powder. Summary of the Invention

[0006] In view of the problems existing in the prior art, the object of the present invention is to provide a method for recovering nickel-cobalt-manganese black powder in a short process. The method performs a specific impurity removal process after acid leaching, uses nickel-cobalt precipitate to preliminarily adjust the pH, and then adds alkali to adjust the pH for precipitation and impurity removal; then, only the manganese element in the impurity-removed liquid is extracted and stripped to obtain a nickel-cobalt raffinate and a manganese strip liquor; the nickel-cobalt raffinate is evaporated and crystallized to obtain nickel-cobalt salt crystals, but a certain amount of evaporation mother liquor is retained and divided into two parts. The first part is directly returned to the impurity removal process, and the second part is precipitated to obtain a nickel-cobalt precipitate and a boron-containing solution. The nickel-cobalt precipitate is then reused in the impurity removal process for preliminarily adjusting the pH. The method has a simple process flow. After effective impurity removal, only manganese is extracted, reducing the acid and alkali consumption and wastewater generation in the extraction stage. In addition, the degree of evaporation and crystallization is controlled to retain the evaporation mother liquor, which is divided into two parts and reused in the impurity removal process, thereby achieving nickel and cobalt enrichment and recovery while reducing the consumption of alkali reagents.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for recovering nickel, cobalt and manganese black powder in a short process, the method comprising:

[0009] (1) acid leaching nickel-cobalt-manganese black powder to obtain a nickel-cobalt-manganese solution and leached residue;

[0010] (2) mixing the nickel-cobalt-manganese solution with a tungsten precipitation agent to perform a tungsten removal reaction to obtain a tungsten-removed liquid and a tungsten-containing slag;

[0011] (3) mixing the tungsten-removed liquid with an oxidant to carry out an oxidation reaction, then adding nickel-cobalt precipitate to preliminarily adjust the pH, and then adding alkali to adjust the pH for a second time to remove impurities, thereby obtaining a de-impurity-removed liquid and de-impurity-removed slag;

[0012] (4) extracting and stripping the manganese element in the impurity-removed liquid to obtain a nickel-cobalt raffinate and a manganese stripping liquid;

[0013] (5) evaporating and crystallizing the nickel-cobalt raffinate to obtain an evaporated mother liquor and nickel-cobalt salt crystals;

[0014] (6) The evaporated mother liquor is divided into two parts, the first part is directly returned to the impurity removal process in step (2), and the second part is precipitated to obtain a nickel-cobalt precipitate and a boron-containing solution, and the nickel-cobalt precipitate is reused in step (3) to perform the preliminary pH adjustment.

[0015] In the method of the present invention, after acid leaching of nickel-cobalt-manganese black powder, a tungsten removal agent is first used to precipitate and remove the tungsten element, based on the characteristics of tungsten impurities and other impurity elements such as aluminum, strontium, zirconium, titanium and boron contained in the nickel-cobalt-manganese black powder. Then, an alkali is added to adjust the pH to generate a precipitate to remove most of the other metal impurity elements. However, before adding the alkali, a specific nickel-cobalt precipitate is used to preliminarily adjust the pH, which can effectively reduce the amount of alkali used. The nickel-cobalt precipitate used initially can use purchased chemical raw materials. As the method proceeds, the nickel-cobalt precipitate can be derived from the nickel-cobalt precipitate obtained by precipitating the second part of the subsequent evaporated mother liquor. The reason for precipitating the second part of the evaporated mother liquor is not only to obtain the nickel-cobalt precipitate, but also to separate the boron and the residual strontium in the boron-containing solution, and to gradually discharge and remove the boron by continuously recycling the evaporated mother liquor into two parts.

[0016] After the impurity removal process, the present invention does not need to extract all the nickel, cobalt and manganese metals during extraction, but only selectively extracts the manganese metal. This saves the acid and alkali required for extracting and stripping nickel and cobalt in the extraction process, and reduces the amount of extraction wastewater generated, thereby further reducing the recovery processing cost. The cost of recycling and treating nickel, cobalt and manganese black powder according to the method of the present invention is 9,406 yuan / ton, while the cost of recycling and treating nickel, cobalt and manganese black powder by the mainstream hydrometallurgical full extraction and full stripping process is 13,987 yuan / ton. The process of the present invention can reduce the cost by 4,581 yuan / ton, which has great application prospects.

[0017] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0018] As a preferred technical solution of the present invention, in step (1), the nickel-cobalt-manganese black powder contains nickel, cobalt, manganese, aluminum, lithium and impurity elements, and the impurity elements include tungsten and at least one of boron, zirconium, titanium or strontium.

[0019] Preferably, the nickel-cobalt-manganese black powder has been pre-processed for lithium extraction.

[0020] It should also be noted that in the present invention, since other chemical reagents are introduced during tungsten removal, such as tungsten precipitation agent ferrous sulfate, an oxidant is first used in the impurity removal process of step (3) to oxidize the metal elements, such as oxidizing ferrous iron to ferric iron, so that it can subsequently generate hydroxide precipitation; therefore, when alkali is added in the impurity removal process for secondary pH adjustment and precipitation removal, the precipitation reaction that occurs includes:

[0021] Fe 3+ +3OH - =Fe(OH)3↓;

[0022] Al3+ +3OH - =Al(OH)3↓;

[0023] Zr 4+ +4OH - =Zr(OH)4↓;

[0024] TiO 2+ +2OH - =TiO(OH)2↓;

[0025] Sr 2+ +2OH - =Sr(OH)2↓.

[0026] “↓” represents precipitation. The generated substances such as iron hydroxide and aluminum hydroxide will also adsorb tungsten, boron and other elements to remove impurities, which is beneficial to improving the impurity removal effect.

[0027] Preferably, the nickel-cobalt-manganese black powder is first prepared into a slurry with water, and then the acid leaching is performed; the solid-liquid ratio of the nickel-cobalt-manganese black powder to water in the slurry is 1g:(3-5)mL, for example, 1g:3mL, 1g:3.2mL, 1g:3.5mL, 1g:3.8mL, 1g:4mL, 1g:4.2mL, 1g:4.5mL, 1g:4.8mL or 1g:5mL, etc.

[0028] As a preferred technical solution of the present invention, in step (1), the acid used for the acid leaching includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

[0029] Preferably, the amount of acid is controlled according to 1 to 3 times the theoretical reaction amount of the nickel-cobalt-manganese black powder, for example, 1 time, 1.2 times, 1.5 times, 1.8 times, 2 times, 2.3 times, 2.5 times, 2.8 times or 3 times.

[0030] Preferably, the acid leaching further uses a reducing agent, and the reducing agent includes at least one of hydrogen peroxide, sodium sulfite or sodium thiosulfate.

[0031] Preferably, the amount of the reducing agent is controlled according to 1 to 1.5 times the theoretical reaction amount of the nickel-cobalt-manganese black powder, for example, 1 time, 1.1 times, 1.2 times, 1.3 times, 1.4 times or 1.5 times.

[0032] Preferably, the acid leaching temperature is 80-90°C, for example, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, and the time is 3-6h, for example, 3h, 3.3h, 3.5h, 3.8h, 4h, 4.2h, 4.5h, 4.8h, 5h, 5.2h, 5.5h, 5.8h or 6h, etc.

[0033] As a preferred technical solution of the present invention, in step (2), the tungsten precipitation agent includes ferrous sulfate, and the tungsten-containing slag includes ferrous tungstate.

[0034] In the present invention, when the tungsten removal agent includes ferrous sulfate, the reaction that occurs includes FeSO4+WO4 2- =FeWO4↓+SO4 2- .

[0035] Preferably, the amount of the tungsten precipitation agent is controlled according to 1 to 1.5 times the theoretical reaction amount of the nickel-cobalt-manganese solution, for example, 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h or 1.5 h.

[0036] Preferably, the reaction temperature for tungsten removal is 40-70°C, for example, 40°C, 43°C, 48°C, 52°C, 56°C, 60°C, 63°C, 67°C or 70°C; the pH is greater than 1.5, for example, 1.52, 1.56, 1.6, 1.63, 1.65, 1.7, 1.73, 1.76, 1.8, 1.9 or 2; and the reaction time is 1-3h, for example, 1h, 1.2h, 1.5h, 1.8h, 2h, 2.3h, 2.5h, 2.8h or 3h.

[0037] As a preferred technical solution of the present invention, in step (3), the oxidant includes hydrogen peroxide,

[0038] Preferably, the amount of the oxidant is controlled according to 1 to 1.5 times the theoretical reaction amount of the tungsten removal solution, for example, 1 time, 1.1 times, 1.2 times, 1.3 times, 1.4 times or 1.5 times.

[0039] Preferably, the oxidation reaction time is 0.5 to 2 h, for example, 0.5 h, 0.8 h, 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h or 2 h.

[0040] As a preferred technical solution of the present invention, in step (3), the nickel-cobalt precipitate used for preliminary pH adjustment includes nickel and cobalt hydroxides and / or nickel and cobalt carbonates.

[0041] Preferably, the pH range for initial pH adjustment is 3.0 to 4.5, such as 3.0, 3.2, 3.5, 3.8, 4, 4.2, 4.4 or 4.5.

[0042] Preferably, the alkali used for the secondary pH adjustment includes liquid alkali and / or soda ash.

[0043] Preferably, the pH range of the secondary pH adjustment is 5.5 to 6.0, such as 5.5, 5.6, 5.7, 5.8, 5.9 or 6.0.

[0044] As a preferred technical solution of the present invention, step (3) also includes mixing the impurity-removing slag with acid and dissolving it to obtain a dissolving solution and insoluble slag; and subjecting the nickel and cobalt elements in the dissolving solution to resin adsorption and desorption to obtain a nickel-cobalt solution and an adsorbed liquid.

[0045] Preferably, the nickel-cobalt-containing solution is mixed with the second portion of the evaporated mother liquor in step (6) to carry out the precipitation together.

[0046] Preferably, the adsorbed liquid is subjected to wastewater treatment.

[0047] As a preferred technical solution of the present invention, in step (4), the manganese stripping solution is deoiled and then used for the synthesis of the ternary material precursor.

[0048] Preferably, in step (4), the nickel-cobalt raffinate is first deoiled to obtain a deoiled liquid, and the deoiled liquid is used for the evaporation crystallization in step (5).

[0049] Preferably, the degreasing agent used for the degreasing comprises activated carbon.

[0050] As a preferred technical solution of the present invention, in step (5), during the evaporation crystallization, the crystallization rate of nickel-cobalt salt crystals obtained from the nickel-cobalt raffinate is controlled to be 70% to 85%, for example, 70%, 72%, 75%, 78%, 80%, 82% or 85%.

[0051] As a preferred technical solution of the present invention, in step (6), the first part of the evaporated mother liquor accounts for 60% to 80% of the evaporated mother liquor, for example, 60%, 63%, 65%, 68%, 70%, 72%, 74%, 76%, 78% or 80%, and the second part accounts for 20% to 40% of the evaporated mother liquor, for example, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38% or 40%, etc.

[0052] Preferably, the precipitant for precipitating the second portion of the evaporated mother liquor comprises liquid caustic soda and / or soda ash.

[0053] Preferably, the boron-containing solution is subjected to wastewater treatment.

[0054] Compared with the existing technical solutions, the present invention has at least the following beneficial effects:

[0055] The method of the present invention has a simple process flow. After effectively removing impurities through a specific impurity removal process, the present invention only selects to extract manganese, reducing acid and alkali consumption and wastewater generation. The present invention retains the evaporated mother liquor by controlling the degree of evaporation and crystallization, and divides the evaporated mother liquor into two parts for reuse in the impurity removal process. This can not only achieve the enrichment and recovery of nickel and cobalt, and the removal of boron, but also can reuse the precipitated nickel and cobalt precipitate in the impurity removal process, effectively reducing the consumption of alkaline reagents. The cost of recycling nickel, cobalt and manganese black powder by the method of the present invention is 9406 yuan / ton, while the cost of recycling nickel, cobalt and manganese black powder by the mainstream hydrometallurgical full extraction and full reaction process is 13987 yuan / ton. The process of the present invention can reduce the cost by 4581 yuan / ton, and has great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a schematic flow chart of the short-process method for recovering nickel-cobalt-manganese black powder in Example 1. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0058] It should be apparent to those skilled in the art that the embodiments are only intended to help understand the present invention and should not be considered as specific limitations of the present invention.

[0059] Example 1

[0060] This embodiment provides a method for recovering nickel, cobalt and manganese black powder in a short process, such as Figure 1 As shown, the following specific steps are included:

[0061] (1) Provide nickel-cobalt-manganese black powder after the lithium extraction process, the main component contents of which are shown in Table 1.

[0062] Table 1. Content of main components in nickel-cobalt-manganese black powder (wt%)

[0063] Ni Co Mn Li Al W Sr Zr Ti B 43.12 6.29 6.92 0.25 0.32 0.21 0.09 0.13 0.16 0.15

[0064] Take 1000g of nickel-cobalt-manganese black powder, add pure water to make slurry at a solid-liquid ratio of 1g:3mL, start stirring and place it in a water bath, then add 1.0 times the theoretical amount of sulfuric acid and 1.3 times the theoretical amount of reducing agent hydrogen peroxide for acid leaching. The acid leaching temperature is 80°C. After reacting for 6h, solid-liquid separation is performed to obtain a nickel-cobalt-manganese solution and leaching residue.

[0065] (2) To the resulting nickel-cobalt-manganese solution containing impurities, tungsten removal agent, ferrous sulfate, in an amount 1.2 times the theoretical amount for reaction with tungstate ions, was added to remove tungsten. The reaction temperature was 70°C, and the pH of the solution was controlled at 2.5 during the reaction. After 1 hour of reaction, solid-liquid separation was performed to obtain a tungsten-removed liquid and a tungsten-containing slag, namely, ferrous tungstate slag. The contents of the main components in the tungsten-removed liquid were tested, and the results are shown in Table 2.

[0066] Table 2. Content of main components in the solution after tungsten removal (g / L)

[0067] Ni Co Mn Li Al W Sr Zr Ti B 99.51 14.35 15.67 0.58 0.71 0.01 0.21 0.3 0.37 0.35

[0068] (3) To the resulting tungsten-removed liquid, 1.2 times the theoretical amount of hydrogen peroxide was added as an oxidant to react with ferrous ions. After the oxidation reaction was carried out for 1 hour, nickel cobalt carbonate was added as a nickel-cobalt precipitate. The pH of the solution was initially adjusted to 3.0. After the pH stabilized, a soda ash solution was added as a base to adjust the pH of the solution to 5.5 for a second time to remove impurities. After the pH stabilized, solid-liquid separation was performed to obtain a de-impurity residue and a de-impurity liquid. The contents of the main components in the de-impurity liquid were tested, and the results are shown in Table 3.

[0069] Table 3. Content of main components in the liquid after impurity removal (g / L)

[0070] Ni Co Mn Li Al W Sr Ti B 91.85 13.12 14.33 0.51 ＜0.001 ＜0.001 0.012 ＜0.001 0.16

[0071] The impurity residue is removed and the pH of the solution is adjusted to 1.5 by adding acid for dissolution. After solid-liquid separation, a dissolved solution and an insoluble residue are obtained. The dissolved solution is adsorbed with a cationic resin to obtain an adsorbed liquid and an adsorption resin. The adsorption resin is desorbed to obtain a nickel-cobalt solution, i.e., a nickel-cobalt sulfate solution. The nickel-cobalt sulfate solution is transferred to step (6), and the adsorbed liquid is disposed of in a wastewater system.

[0072] (4) The obtained impurity-removed liquid is extracted and separated from manganese in the solution using an extractant (P204), and then stripped to obtain a nickel-cobalt raffinate, i.e., a nickel-cobalt sulfate raffinate, and a manganese strip solution, i.e., a manganese sulfate strip solution. The manganese sulfate strip solution is deoiled with activated carbon and can be used as a raw material for the synthesis of ternary positive electrode material precursors. The nickel-cobalt sulfate strip solution is deoiled with activated carbon to obtain a deoiled liquid. The content of the main components in the manganese sulfate strip solution was tested, and the results are shown in Table 4.

[0073] Table 4. Content of main components in manganese sulfate stripping solution (g / L)

[0074] Ni Co Mn Li Al W Sr Zr Ti B 0.002 0.007 118.5 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001

[0075] (5) The deoiled liquid was subjected to evaporation crystallization, and the nickel-cobalt crystallization rate was controlled to be 70% during the evaporation crystallization to obtain the product nickel-cobalt salt crystals, i.e., nickel-cobalt sulfate crystals, and the evaporation mother liquor; the content of the main components in the nickel-cobalt sulfate crystals was tested, and the results are shown in Table 5.

[0076] Table 5. Content of main components in nickel cobalt sulfate crystals (wt%)

[0077] Ni Co Mn Li Na Al W Sr Zr Ti B 21.79 3.11 0.0005 0.0012 0.012 0.0001 0.0001 0.0001 0.0001 0.0001 0.0005

[0078] (6) 80% of the evaporated mother liquor is returned as the first part to the impurity removal process of step (3) and mixed with the tungsten-removed liquid; the remaining 20% of the evaporated mother liquor is combined with the nickel-cobalt sulfate solution from step (3) as the second part, and then a soda ash solution is added to completely precipitate the nickel and cobalt to obtain a nickel-cobalt precipitate and a boron-containing solution. The nickel-cobalt precipitate is returned to the impurity removal process of step (3), and the boron-containing solution is disposed of in the wastewater system.

[0079] Example 2

[0080] This embodiment provides a method for recovering nickel, cobalt and manganese black powder in a short process, comprising the following specific steps:

[0081] (1) Provide nickel, cobalt and manganese black powder after the lithium extraction process, the main component contents of which are shown in Table 6.

[0082] Table 6. Content of main components in nickel-cobalt-manganese black powder (wt%)

[0083] Ni Co Mn Li Al W Sr Zr Ti B 38.27 7.41 12.32 0.34 0.26 0.15 0.11 0.14 0.19 0.2

[0084] Take 1500g of nickel-cobalt-manganese black powder, add pure water to make slurry at a solid-liquid ratio of 1g:4mL, start stirring and place it in a water bath, then add 1.0 times the theoretical amount of sulfuric acid and 1.2 times the theoretical amount of reducing agent hydrogen peroxide for acid leaching. The acid leaching temperature is 90°C. After reacting for 3h, solid-liquid separation is performed to obtain a nickel-cobalt-manganese solution and leaching residue.

[0085] (2) To the resulting nickel-cobalt-manganese solution containing impurities, tungsten removal agent ferrous sulfate (1.5 times the theoretical amount for reaction with tungstate ions) was added to remove tungsten. The reaction temperature was 60°C, and the pH of the solution was controlled at 2.0 during the reaction. After 2 hours of reaction, solid-liquid separation was performed to obtain a tungsten-removed liquid and a tungsten-containing slag, namely, ferrous tungstate slag. The contents of the main components in the tungsten-removed liquid were tested, and the results are shown in Table 7.

[0086] Table 7. Content of main components in the solution after tungsten removal (g / L)

[0087] Ni Co Mn Li Al W Sr Zr Ti B 85.78 16.61 27.61 0.76 0.58 0.006 0.22 0.31 0.41 0.42

[0088] (3) To the resulting tungsten-removed solution, 1.1 times the theoretical amount of hydrogen peroxide was added as an oxidant to react with ferrous ions. After a 2-hour reaction, nickel cobalt carbonate was added as a nickel-cobalt precipitate. The pH of the solution was initially adjusted to 3.5. After the pH stabilized, a soda ash solution was added as a base to adjust the pH of the solution to 6.0 for a second time to remove impurities. After the pH stabilized, solid-liquid separation was performed to obtain a de-impurity residue and a de-impurity liquid. The contents of the main components in the de-impurity liquid were tested, and the results are shown in Table 8.

[0089] Table 8. Content of main components in the liquid after impurity removal (g / L)

[0090] Ni Co Mn Li Al W Sr Ti B 77.65 15.16 24.39 0.63 ＜0.001 ＜0.001 0.008 ＜0.001 ＜0.001

[0091] The impurity residue is removed and the pH of the solution is adjusted to 2.0 by adding acid for dissolution. After solid-liquid separation, a dissolved solution and an insoluble residue are obtained. The dissolved solution is adsorbed with a cationic resin to obtain an adsorbed liquid and an adsorption resin. The adsorption resin is desorbed to obtain a nickel-cobalt solution, i.e., a nickel-cobalt sulfate solution. The nickel-cobalt sulfate solution is transferred to step (6), and the adsorbed liquid is disposed of in a wastewater system.

[0092] (4) The obtained impurity-removed liquid is extracted and separated from manganese by an extractant, and then stripped to obtain a nickel-cobalt raffinate, i.e., a nickel-cobalt sulfate raffinate, and a manganese strip solution, i.e., a manganese sulfate strip solution. The manganese sulfate strip solution is deoiled with activated carbon and can be used as a raw material for the synthesis of ternary positive electrode material precursors. The nickel-cobalt sulfate strip solution is deoiled with activated carbon to obtain a deoiled liquid. The content of the main components in the manganese sulfate strip solution was tested, and the results are shown in Table 9.

[0093] Table 9. Content of main components in manganese sulfate stripping solution (g / L)

[0094] Ni Co Mn Li Al W Sr Zr Ti B 0.001 0.003 111.5 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001

[0095] (5) The deoiled liquid was subjected to evaporation crystallization, and the nickel-cobalt crystallization rate was controlled to be 85% during the evaporation crystallization to obtain the product nickel-cobalt salt crystals, i.e., nickel-cobalt sulfate crystals, and the evaporated mother liquor; the content of the main components in the nickel-cobalt sulfate crystals was tested, and the results are shown in Table 10.

[0096] Table 10. Content of main components in nickel cobalt sulfate crystals (wt%)

[0097] Ni Co Mn Li Na Al W Sr Zr Ti B 20.74 4.07 0.0005 0.0019 0.021 0.0001 0.0001 0.0001 0.0001 0.0001 0.0006

[0098] (6) 60% of the evaporated mother liquor is returned as the first part to the impurity removal process of step (3) and mixed with the tungsten-removed liquid; the remaining 40% of the evaporated mother liquor is combined with the nickel cobalt sulfate solution from step (3) as the second part, and then a soda ash solution is added to completely precipitate the nickel and cobalt to obtain a nickel cobalt precipitate and a boron-containing solution. The nickel cobalt precipitate is returned to the impurity removal process of step (3), and the boron-containing solution is disposed of in the wastewater system.

[0099] Example 3

[0100] This embodiment provides a method for recovering nickel, cobalt and manganese black powder in a short process, comprising the following specific steps:

[0101] (1) Provide nickel-cobalt-manganese black powder after the lithium extraction process, the main component contents of which are shown in Table 11.

[0102] Table 11. Content of main components in nickel-cobalt-manganese black powder (wt%)

[0103] Ni Co Mn Li Al W Sr Zr Ti B 44.82 4.39 6.35 0.27 0.53 0.13 0.07 0.15 0.12 0.17

[0104] Take 800g of nickel-cobalt-manganese black powder, add pure water to make slurry at a solid-liquid ratio of 1g:5mL, start stirring and place in a water bath, then add 1.0 times the theoretical amount of sulfuric acid and 1.1 times the theoretical amount of reducing agent hydrogen peroxide for acid leaching. The acid leaching temperature is 85°C. After reacting for 4h, solid-liquid separation is performed to obtain a nickel-cobalt-manganese solution and leaching residue.

[0105] (2) To the resulting nickel-cobalt-manganese solution containing impurities was added 1.3 times the theoretical amount of ferrous sulfate (a tungsten removal agent) to remove tungsten. The reaction temperature was 65°C, and the pH of the solution was controlled at 2.5 during the reaction. After 1.5 hours of reaction, solid-liquid separation was performed to obtain a tungsten-removed solution and a tungsten-containing slag, namely, ferrous tungstate slag. The contents of the main components in the tungsten-removed solution were tested, and the results are shown in Table 12.

[0106] Table 12. Content of main components in the solution after tungsten removal (g / L)

[0107]

[0108]

[0109] (3) To the resulting tungsten-removed solution, 1.2 times the theoretical amount of hydrogen peroxide was added as an oxidant to react with ferrous ions. After a 1-hour reaction, nickel cobalt carbonate was added as a nickel-cobalt precipitate. The pH of the solution was initially adjusted to 4.0. After the pH stabilized, a soda ash solution was added as a base to adjust the pH of the solution to 5.6 for secondary removal of impurities. After the pH stabilized, solid-liquid separation was performed to obtain a de-impurity residue and a de-impurity liquid. The contents of the main components in the de-impurity liquid were tested, and the results are shown in Table 13.

[0110] Table 13. Content of main components in the liquid after impurity removal (g / L)

[0111] Ni Co Mn Li Al W Sr Ti B 73.92 7.05 9.87 0.35 ＜0.001 ＜0.001 0.011 ＜0.001 ＜0.001

[0112] The impurity residue is removed and the pH of the solution is adjusted to 2.0 by adding acid for dissolution. After solid-liquid separation, a dissolved solution and an insoluble residue are obtained. The dissolved solution is adsorbed with a cationic resin to obtain an adsorbed liquid and an adsorption resin. The adsorption resin is desorbed to obtain a nickel-cobalt solution, i.e., a nickel-cobalt sulfate solution. The nickel-cobalt sulfate solution is transferred to step (6), and the adsorbed liquid is disposed of in a wastewater system.

[0113] (4) The obtained impurity-removed liquid is extracted and separated from manganese by an extractant, and then stripped to obtain a nickel-cobalt raffinate, i.e., a nickel-cobalt sulfate raffinate, and a manganese strip solution, i.e., a manganese sulfate strip solution. The manganese sulfate strip solution is deoiled with activated carbon and can be used as a raw material for the synthesis of ternary positive electrode material precursors. The nickel-cobalt sulfate strip solution is deoiled with activated carbon to obtain a deoiled liquid. The content of the main components in the manganese sulfate strip solution was tested, and the results are shown in Table 14.

[0114] Table 14. Content of main components in manganese sulfate stripping solution (g / L)

[0115] Ni Co Mn Li Al W Sr Zr Ti B 0.003 0.008 123.4 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001

[0116] (5) The deoiled liquid was subjected to evaporation crystallization, and the nickel-cobalt crystallization rate was controlled to be 80% during the evaporation crystallization to obtain the product nickel-cobalt salt crystals, i.e., nickel-cobalt sulfate crystals, and the evaporation mother liquor; the content of the main components in the nickel-cobalt sulfate crystals was tested, and the results are shown in Table 15.

[0117] Table 15. Content of main components in nickel cobalt sulfate crystals (wt%)

[0118] [[ID=6***]]Ni Co Mn Li Na Al W Sr Zr Ti B 21.67 2.69 0.0005 0.0012 0.012 0.0001 0.0001 0.0001 0.0001 0.0001 0.0005

[0119] (6) 70% of the evaporated mother liquor is returned as the first part to the impurity removal process of step (3) and mixed with the tungsten-removed liquid; the remaining 30% of the evaporated mother liquor is combined with the nickel cobalt sulfate solution from step (3) as the second part, and then a soda ash solution is added to completely precipitate the nickel and cobalt to obtain a nickel cobalt precipitate and a boron-containing solution. The nickel cobalt precipitate is returned to the impurity removal process of step (3), and the boron-containing solution is disposed of in the wastewater system.

[0120] Comparative Example 1

[0121] This comparative example provides a method for recovering nickel-cobalt-manganese black powder. In step (2), no tungsten removal agent is used for tungsten removal. The impurity nickel-cobalt-manganese solution is directly subjected to step (3). Except for the above, other conditions are exactly the same as those in Example 1.

[0122] In this comparative example, the contents of the main components in the impurity-removed liquid, manganese sulfate stripping liquid, and nickel cobalt sulfate crystals were tested, and the results are shown in Table 16, Table 17, and Table 18, respectively.

[0123] Table 16. Content of main components in the liquid after impurity removal (g / L)

[0124] Ni Co Mn Li Al W Sr Ti B 92.34 13.55 13.97 0.48 ＜0.001 0.35 0.013 ＜0.001 0.31

[0125] Table 17. Content of main components in manganese sulfate stripping solution (g / L)

[0126] Ni Co Mn Li Al W Sr Zr Ti B 0.002 0.006 116.7 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001

[0127] Table 18. Content of main components in nickel cobalt sulfate crystals (wt%)

[0128] Ni Co Mn Li Na Al W Sr Zr Ti B 21.65 3.04 0.0003 0.0012 0.015 0.0001 0.0247 0.0001 0.0001 0.0001 0.0007

[0129] Comparative Example 2

[0130] This comparative example provides a method for recovering nickel-cobalt-manganese black powder. In step (2), the method does not use a tungsten removal agent to remove tungsten. Instead, the tungsten element in the nickel-cobalt-manganese solution is extracted to remove tungsten. The pH of the nickel-cobalt-manganese solution is adjusted to 2.5, and then a primary amine extractant C is added. 17 H 35 NH2 is extracted to obtain a raffinate for impurity removal in step (3). Except for the above, other conditions are exactly the same as those in Example 1.

[0131] In this comparative example, the contents of the main components in the impurity-removed liquid, manganese sulfate stripping liquid, and nickel cobalt sulfate crystals were tested, and the results are shown in Table 19, Table 20, and Table 21, respectively.

[0132] Table 19. Content of main components in the liquid after impurity removal (g / L)

[0133] Ni Co Mn Li Al W Sr Ti B 82.33 11.93 12.88 0.46 ＜0.001 0.003 0.008 ＜0.001 0.15

[0134] Table 20. Content of main components in manganese sulfate stripping solution (g / L)

[0135] Ni Co Mn Li Al W Sr Zr Ti B 0.003 0.005 115.9 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001

[0136] Table 21. Content of main components in nickel cobalt sulfate crystals (wt%)

[0137] Ni Co Mn Li Na Al W Sr Zr Ti B 19.35 2.83 0.0003 0.0014 0.065 0.0001 0.0001 0.0001 0.0001 0.0001 0.0003

[0138] Comparative Example 3

[0139] This comparative example provides a method for recovering nickel, cobalt and manganese black powder. Step (1) of the method is the same as that of Example 1, and step (2) is not performed. The remaining steps are as follows:

[0140] (3) adding nickel cobalt carbonate to the nickel-cobalt-manganese solution obtained in step (1) to preliminarily adjust the pH of the solution to 3.0, adding a soda ash solution as a base to adjust the pH of the solution to 5.5 after the pH stabilizes, thereby removing impurities, and performing solid-liquid separation after the pH stabilizes to obtain a decontaminated slag and a decontaminated liquid;

[0141] The impurity residue is removed and acid is added to adjust the pH of the solution to 1.5 for dissolution. After solid-liquid separation, a dissolved solution and an insoluble residue are obtained. The dissolved solution is adsorbed with a cationic resin to obtain an adsorbed liquid and an adsorption resin. The adsorption resin is desorbed to obtain a nickel-cobalt solution, i.e., a nickel-cobalt sulfate solution. The nickel-cobalt sulfate solution is transferred to step (5), and the adsorbed liquid is disposed of in a wastewater system.

[0142] (4) The obtained impurity-removed liquid is subjected to extraction with an extractant (P204) to separate manganese from the solution, and then stripped to obtain a nickel-cobalt raffinate, i.e., a nickel-cobalt sulfate raffinate, and a manganese strip solution, i.e., a manganese sulfate strip solution; the manganese sulfate strip solution can be used as a raw material for the synthesis of a ternary positive electrode material precursor after degreasing with activated carbon; the nickel and cobalt in the nickel-cobalt sulfate raffinate are then extracted (using an extractant P507) and stripped to obtain a nickel-cobalt sulfate solution, and the raffinate after the nickel and cobalt are extracted is disposed of in a wastewater system.

[0143] (5) The nickel cobalt sulfate solution obtained after desorption by the adsorption resin in step (3) is mixed with the nickel cobalt sulfate solution obtained in step (4), and deoiled with activated carbon to obtain a deoiled liquid, and the deoiled liquid is evaporated and crystallized. During the evaporation and crystallization, the nickel cobalt crystallization rate is controlled to be 100% to obtain product nickel cobalt salt crystals, i.e., nickel cobalt sulfate crystals.

[0144] In this comparative example, the main component contents in the impurity-removed liquid, the manganese sulfate stripping liquid, the nickel cobalt sulfate solution mixed in step (4), and the nickel cobalt sulfate crystals were tested, and the results are shown in Table 22, Table 23, Table 24 and Table 25, respectively.

[0145] Table 22. Content of main components in the liquid after impurity removal (g / L)

[0146] Ni Co Mn Li Al W Sr Zr Ti B 92.43 13.51 14.12 0.47 ＜0.001 0.06 0.012 ＜0.001 ＜0.001 0.19

[0147] Table 23. Content of main components in manganese sulfate stripping solution (g / L)

[0148] Ni Co Mn Li Al W Sr Zr Ti B 0.002 0.007 118.5 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001 ＜0.001

[0149] Table 24. Content of main components in nickel cobalt sulfate solution (g / L)

[0150]

[0151] Table 25. Content of main components in nickel cobalt sulfate crystals (g / L)

[0152] Ni Co Mn Li Na Al W Sr Zr Ti B 21.79 3.17 0.0002 0.0003 0.015 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001

[0153] Taking the methods of Example 1 and Comparative Example 3 as the measurement basis, and processing 10,000 tons of nickel-cobalt-manganese black powder annually as the measurement amount, the process costs of Example 1 and Comparative Example 1 when recovering 1 ton of nickel-cobalt-manganese metal are shown in Table 26.

[0154] Table 26. Cost of recovering 1 ton of nickel, cobalt and manganese in Example 1 and Comparative Example 3 (Yuan)

[0155]

[0156]

[0157] From the above examples and comparative examples, it can be seen that the impurities in the manganese sulfate solution and nickel cobalt sulfate crystals obtained in the examples are very low, and the proportion of impurities other than the main metal and sodium element is more than 40,000 times. Since comparative example 1 did not remove tungsten, the tungsten impurity content in the nickel cobalt sulfate crystals obtained by evaporation crystallization was as high as 247ppm. In comparative example 2, extraction was used to remove tungsten. Although the tungsten content in the nickel cobalt sulfate crystals obtained by evaporation crystallization was low, at the same level as in Example 1, the sodium impurity content in the crystals was as high as 650ppm, much higher than 120ppm in Example 1. This is because the pH of the raffinate was reduced during the extraction and removal of tungsten, resulting in the need to add alkali to neutralize the residual acid, and the introduction of more alkaline reagents. The impurity content in the manganese sulfate solution and nickel cobalt sulfate crystals obtained by the mainstream full extraction and full reverse process in comparative example 3 was basically consistent with that in the examples. In terms of cost calculation, the cost of recovering one ton of metal using the method of Example 1 is approximately 9,406 yuan, while the cost of recovering one ton of metal using the process of Comparative Example 3 is approximately 13,987 yuan. The method of Example 1 can save 4,581 yuan per ton of nickel, cobalt, and manganese metal compared to the method of Comparative Example 3. The main reason is that the method of Comparative Example 3 uses full extraction and stripping during extraction, consuming a large amount of acid and liquid alkali and generating a large amount of wastewater, resulting in higher recovery costs. Based on the annual recovery of 10,000 tons of nickel, cobalt, and manganese black powder, the method provided by the present invention is expected to save 45.81 million yuan compared to the mainstream full extraction and stripping process, showing great application prospects.

[0158] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0159] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0160] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for recovering nickel, cobalt and manganese black powder in a short process, characterized in that: The method comprises: (1) acid leaching nickel-cobalt-manganese black powder to obtain a nickel-cobalt-manganese solution and leached residue; (2) mixing the nickel-cobalt-manganese solution with a tungsten precipitation agent to carry out a tungsten removal reaction to obtain a tungsten-removed liquid and a tungsten-containing slag; (3) mixing the tungsten-removed liquid with an oxidant to carry out an oxidation reaction, then adding nickel-cobalt precipitate to preliminarily adjust the pH, and then adding alkali to adjust the pH for a second time to remove impurities, thereby obtaining a de-impurity-removed liquid and de-impurity-removed slag; (4) extracting and stripping the manganese element in the impurity-removed liquid to obtain a nickel-cobalt raffinate and a manganese stripping liquid; (5) evaporating and crystallizing the nickel-cobalt raffinate to obtain an evaporated mother liquor and nickel-cobalt salt crystals; (6) The evaporated mother liquor is divided into two parts, the first part is directly returned to the impurity removal process in step (3), and the second part is precipitated to obtain a nickel-cobalt precipitate and a boron-containing solution, and the nickel-cobalt precipitate is reused in step (3) to perform the preliminary pH adjustment.

2. The method for recovering nickel-cobalt-manganese black powder by a short process according to claim 1, characterized in that: In step (1), the nickel-cobalt-manganese black powder contains nickel, cobalt, manganese, aluminum, lithium and impurity elements, wherein the impurity elements include tungsten and at least one of boron, zirconium, titanium or strontium; Preferably, the nickel-cobalt-manganese black powder is pre-processed for lithium extraction; Preferably, the nickel-cobalt-manganese black powder is first prepared into a slurry with water, and then the acid leaching is performed; the solid-to-liquid ratio of the nickel-cobalt-manganese black powder to water in the slurry is 1 g: (3-5) mL.

3. The method for recovering nickel-cobalt-manganese black powder by a short process according to claim 1 or 2, characterized in that: In step (1), the acid used for the acid leaching includes at least one of sulfuric acid, hydrochloric acid or nitric acid; Preferably, the amount of acid is controlled according to 1 to 3 times the theoretical reaction amount for reacting with the nickel-cobalt-manganese black powder; Preferably, the acid leaching further uses a reducing agent, and the reducing agent includes at least one of hydrogen peroxide, sodium sulfite or sodium thiosulfate; Preferably, the amount of the reducing agent is controlled according to 1 to 1.5 times the theoretical reaction amount for reacting with the nickel-cobalt-manganese black powder; Preferably, the acid leaching temperature is 80-90° C. and the time is 3-6 hours.

4. The method for recovering nickel-cobalt-manganese black powder in a short process according to any one of claims 1 to 3, characterized in that: In step (2), the tungsten precipitation agent includes ferrous sulfate, and the tungsten-containing slag includes ferrous tungstate; Preferably, the amount of the tungsten precipitation agent is controlled according to 1 to 1.5 times the theoretical reaction amount of the nickel-cobalt-manganese solution; Preferably, the temperature of the tungsten removal reaction is 40-70° C., the pH value is greater than 1.5, and the time is 1-3 hours.

5. The method for recovering nickel-cobalt-manganese black powder in a short process according to any one of claims 1 to 4, characterized in that: In step (3), the oxidant includes hydrogen peroxide; Preferably, the amount of the oxidant is controlled according to 1 to 1.5 times the theoretical reaction amount of the tungsten removal solution; Preferably, the oxidation reaction time is 0.5 to 2 hours.

6. The method for recovering nickel-cobalt-manganese black powder by a short process according to any one of claims 1 to 5, characterized in that: In step (3), the nickel-cobalt precipitate used for preliminary pH adjustment includes nickel and cobalt hydroxides and / or nickel and cobalt carbonates; Preferably, the pH range for initial pH adjustment is 3.0 to 4.5; Preferably, the alkali used for the secondary pH adjustment includes liquid caustic soda and / or soda ash; Preferably, the pH range of the secondary pH adjustment is 5.5 to 6.

0.

7. The method for recovering nickel-cobalt-manganese black powder by a short process according to any one of claims 1 to 6, characterized in that: Step (3) further comprises mixing the impurity-removed slag with an acid and dissolving the mixture to obtain a dissolving solution and an insoluble slag; subjecting the nickel and cobalt elements in the dissolving solution to resin adsorption and desorption to obtain a nickel-cobalt solution and an adsorbed solution; Preferably, the nickel-cobalt-containing solution is mixed with the second portion of the evaporated mother liquor in step (6) to carry out the precipitation together; Preferably, the adsorbed liquid is subjected to wastewater treatment.

8. The method for recovering nickel-cobalt-manganese black powder by a short process according to any one of claims 1 to 7, characterized in that: In step (4), the manganese stripping solution is deoiled and then used for the synthesis of the ternary material precursor; Preferably, in step (4), the nickel-cobalt raffinate is first deoiled to obtain a deoiled liquid, and the deoiled liquid is used for the evaporation crystallization in step (5); Preferably, the degreasing agent used for the degreasing comprises activated carbon.

9. The method for recovering nickel-cobalt-manganese black powder in a short process according to any one of claims 1 to 8, characterized in that: In step (5), during the evaporation crystallization, the crystallization rate of nickel-cobalt salt crystals obtained from the nickel-cobalt raffinate is controlled to be 70% to 85%.

10. The method for recovering nickel-cobalt-manganese black powder in a short process according to any one of claims 1 to 9, characterized in that: In step (6), the first portion of the evaporated mother liquor accounts for 60% to 80% of the evaporated mother liquor, and the second portion accounts for 20% to 40% of the evaporated mother liquor; Preferably, the precipitant for precipitating the second portion of the evaporated mother liquor comprises liquid caustic soda and / or soda ash; Preferably, the boron-containing solution is subjected to wastewater treatment.

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